Balloon catheter and method for manufacturing it

ABSTRACT

A balloon catheter includes a catheter tube and an inflatable balloon. The ends of the balloon are attached to the catheter tube. The outside surface of the balloon in an uninflated state is provided with a relief structure which in an inflated state of the balloon is substantially disappeared. A method for producing such a relief structure is by winding a wire helically around the outer surface of the balloon.

This application is a continuation of U.S. patent application Ser. No.10/140,524, filed May 7, 2002 which is now U.S. Pat. No. 8,083,761, thefull disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a balloon catheter comprising acatheter tube and an inflatable balloon which at its ends is attached tothe catheter tube. The invention further relates to a method ofmanufacturing a balloon catheter.

BACKGROUND INFORMATION

Balloon catheters of this type are generally known and are used fordilating vessels and lumina. In order to pass the balloon cathetereasily and safely through the vessels and lumina and to position it atthe required place for dilatation, it is important that the ballooncatheter has a small profile and is sufficiently flexible.

The object of the invention is therefore to provide an improved ballooncatheter.

BRIEF SUMMARY OF THE INVENTION

The balloon catheter according to the invention is characterized in thatthe outside surface of the balloon in an uninflated state is providedwith a relief structure which in an inflated state of the balloon issubstantially disappeared.

Tests have shown that with a relief structure on the outside surface ofthe balloon, a catheter is obtained that is more flexible than astandard balloon catheter. The balloon catheter according to theinvention can therefore be passed more easily and more safely throughvessels and lumina to the point of dilatation. Because of itsflexibility, the catheter will be able to adapt better to a bend in avessel or a lumen, thus reducing the risk of damage to the vessel orlumen.

The required relief structure may have different embodiments, butpreferably comprises at least one groove that extends at leasttransversely in the longitudinal direction of the balloon in order togive the catheter the required flexibility in a direction transverse tothe longitudinal direction thereof.

The groove preferably extends at a predetermined angle with respect tothe longitudinal direction of the balloon. According to a preferredembodiment the groove extends helically from one end to the other end ofthe balloon, over the outside surface thereof.

According to another embodiment, the relief structure comprises two ormore grooves that extend helically from one end to the other end of theballoon, crossing each other. Tests have shown that with such a reliefstructure a very flexible balloon catheter is obtained which also has arelatively small profile.

The invention also relates to a method for producing a balloon cathetercomprising attaching the ends of an inflatable balloon to a cathetertube, whereby according to the invention the outside surface of theballoon is provided with a relief structure.

According to an embodiment of the invention, the relief structure isproduced on the application of heat in order to deform the elasticmaterial of the balloon.

The relief structure is also preferably produced on the surface of theballoon by applying a high pressure to the inside of the balloon.

According to a very inexpensive method, the relief structure is producedon the surface of the balloon by winding a wire around the balloon inthe form of a helix.

According to another simple method, the relief structure is produced onthe surface of the balloon by taking up the balloon in acounter-pressure body that has the relief structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail on the basis of the drawingsattached. The drawings show:

FIG. 1A is a side view of a first embodiment of a balloon catheter in anuninflated state,

FIG. 1B is a side view of the catheter in FIG. 1A in an inflated state,

FIG. 2A is a side view of a second embodiment of a balloon catheter inan uninflated state, and

FIG. 2B is a side view of the catheter of FIG. 2A in an inflated state.

DETAILED DESCRIPTION OF THE INVENTION

A balloon catheter according to the invention comprises a catheter tube1 and an inflatable balloon 2, which at its ends is attached to thecatheter tube 1. In an uninflated state (FIGS. 1A and 2A), the outsidesurface of balloon 2 has a relief structure 4 that in the inflated statehas virtually or completely disappeared (FIGS. 1B and 2B). The reliefstructure gives the catheter its required flexibility.

In the first embodiment according to FIGS. 1A and 1B, the reliefstructure 4 consists of one groove 5, which extends helically from oneend 3 to the other end 3 of the balloon 2, over the outside surfacethereof. The uninflated balloon 2 has thereby obtained a helical reliefsurface. In the second embodiment according to FIGS. 2A and 2B, therelief structure 4 consists of two grooves 5, 6, which extend helicallyfrom one end 3 to the other end 3 of the balloon 2 and thereby crosseach other. The uninflated balloon 2 has hereby obtained a padded reliefsurface.

Other relief structures are of course possible, provided that the reliefstructure on the catheter creates the necessary flexibility in adirection transverse to the longitudinal direction of the balloon.

One way of obtaining the relief structure as shown in the drawings is bywinding a wire helically around the balloon 2. If the wire is wound onlyin the forward direction, the structure according to FIG. 1A isobtained, and if the wire is also wound in the return direction, thestructure in FIG. 2A is obtained. After the wire has been wound aroundthe balloon, a sleeve is pulled over the balloon. Subsequently, with theapplication of raised pressure to the inside of the balloon, the balloonis heated in such a way that, in an uninflated state, the balloonobtains a relief structure that on dilating of the balloon at thedilatation site in the vessel or lumen will virtually or completelydisappear. The sleeve is then removed and the balloon catheter can beinserted into a vessel or a lumen.

Instead of winding a wire, the balloon may be placed in a mould, whichis provided with the relief pattern required in order for it to obtain,under raised pressure and temperature, the relief structure required.

Before the balloon is provided with its relief structure, preferably itis folded in the usual way in order to reduce its profile. By applyingthe relief structure, the profile will be reduced still further as anadditional, advantageous effect.

The usual way of folding a balloon mounted on a catheter involves thefolding of the uninflated balloon wall so that wall overlaps itself anddefines portions of the balloon wall that are within a fold. A foldedballoon has exposed portions of the folded balloon that are exposed toan exterior environment of the balloon, and unexposed portions that arenot exposed because those portions are contained within a fold of thefolded balloon.

Note that, although it is not shown in the drawings, it is possible toprovide the outside surface of the balloon with various helical groovesthat cross each other.

1. A balloon catheter comprising: a catheter tube disposed on alongitudinal axis; and an inflatable balloon having opposite terminalends and an outside surface, the terminal ends of the balloon attachedto the catheter tube, wherein in an uninflated and folded state, theoutside surface that is exposed when the balloon is folded is providedwith a groove, which is substantially disappeared when the balloon is inan inflated state at an intended operating pressure during use, and theoutside surface that is within a fold of the balloon and not exposeddoes not have the groove, and wherein the groove fully extends from oneterminal end to another terminal end of the opposite terminal ends ofthe balloon and only over the outside surface that is exposed when theballoon is folded.
 2. The balloon catheter according to claim 1, wherebythe groove fully extends at least transversely in a longitudinaldirection of the balloon.
 3. The balloon catheter according to claim 2,whereby the groove fully extends at a predetermined angle with regard tothe longitudinal direction of the balloon.
 4. The balloon catheteraccording to claim 2, whereby the groove extends helically from the oneterminal end to the another terminal end of the balloon.
 5. The ballooncatheter according to claim 4, further including another groove thatfully extends helically from the one terminal end to the anotherterminal end of the balloon and cross each other.
 6. The ballooncatheter of claim 1, wherein the balloon includes a first section at oneterminal end having a first radial dimension less than a second radialdimension of a second section of the balloon in an inflated state,wherein the groove extends along both the first section and the secondsection in the uninflated and folded state.
 7. The balloon catheter ofclaim 1, wherein the balloon includes a frusto-conical portion adjacenteach terminal end, and wherein the groove extends at least partiallyalong the frusta-conical portion in the uninflated and folded state. 8.A catheter at least partially formed by a manufacturing structure, saidcatheter comprising: a catheter shaft disposed on a longitudinal axis;and a balloon mounted on the catheter shaft, the balloon disposed on theshaft and having a continuous balloon wall that is circumferentiallyfolded upon itself about the axis, portions of the folded balloon wallthat are exposed to an exterior environment being a first portion of theballoon wall and portions of the folded balloon wall that are notexposed to the exterior environment being a second portion of theballoon wall, a plurality of grooves created by the manufacturingstructure, said grooves disposed on the first portion of the balloonwall and not disposed on the second portion of the balloon wall, each ofthe plurality of grooves disposed to align with an adjacent one of theplurality of grooves and each of the plurality of grooves substantiallydisappeared when the balloon is in an inflated state at an intendedoperating pressure during use, wherein the catheter does not include astent for deployment, and wherein the manufacturing structure whichcreated the plurality of grooves is removed before use.
 9. The catheterof claim 8, the balloon having a plurality of circumferential folds. 10.The catheter of claim 8, the plurality of aligned grooves are disposedto join together to form a substantially continuous groove extendingcircumferentially about the axis on the first portion of the balloonwall when the balloon is in an uninflated and folded state.
 11. Thecatheter of claim 8, the plurality of aligned grooves are disposed tojoin together to form first and second substantially continuous groovesextending circumferentially about the axis on the first portion of theballoon wall when the balloon is in an uninflated and folded state. 12.The catheter of claim 11, the first and second substantially continuousgrooves intersecting each other.
 13. The balloon of claim 8, wherein theplurality of grooves fully extend from a first end of the balloon to asecond, opposite end of the balloon.